Solid state lasers are currently in use and have many desirable qualities with regard to compactness, robustness and reliability. They also are capable of producing high optical to optical conversion efficiency and, thus, have the potential for producing high energy output. These fiber optic lasers have a multitude of applications including, for example, industrial, military and medical technologies.
Such devices, however, have shortcomings that may make their application impractical in many instances. For example, most known fiber optic lasers that are powered or pumped by solid state devices, such as diode lasers, require multiple optical components to be aligned and positioned relative to each other with a high degree of accuracy. For example, many edge emitting diode lasers used to pump the core of a fiber optic laser element use a cylindrical lens on the output of the diode laser to collimate the divergent output of the diode laser and focus the energy onto the fiber optic element. The fixturing and alignment of these components can be tedious and expensive to produce.
Also, one coupling method in use involves focusing the energy from a number of diode laser emitters onto the small end surface of a fiber optic laser. This technique can produce high temperatures and energy related stresses on the input end surface of the optical fiber. Such temperatures and stresses can result in damage to the fiber input that can reduce efficiency and potentially destroy the fiber altogether. Other methods incorporate multiple fiber optic waveguides that individually guide pumping energy from a number of individual diode lasers to the input end of a fiber optic laser having a laseable core. As such, the energy from the individual fiber optic waveguides can then be coupled to the pump cladding surrounding the laseable core. Such an arrangement, in addition to being tedious and expensive to produce, also produces large optical losses in the optical train from the individual diode lasers to the laseable core of the fiber optic laser. In some embodiments having this configuration, the cumulative optical losses can be up to 60%.
What has been needed are systems for efficiently and reliably coupling electromagnetic energy from a small solid state electronic component, such as a diode laser, into a lasing core of fiber optic element that are easy to manufacture, reliable, efficient and which do not put undue stresses on the optical components therein.